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QDateTime Class Reference
^{[QtCore module]}

The QDateTime class provides date and time functions. More...

Methods

• __init__ (self)
• __init__ (self, QDateTime other)
• __init__ (self, QDate)
• __init__ (self, QDate date, QTime time, Qt.TimeSpec timeSpec = Qt.LocalTime)
• __init__ (self, int y, int m, int d, int h, int m, int s = 0, int msec = 0, int timeSpec = 0)
• QDateTime addDays (self, int days)
• QDateTime addMonths (self, int months)
• QDateTime addMSecs (self, int msecs)
• QDateTime addSecs (self, int secs)
• QDateTime addYears (self, int years)
• QDate date (self)
• int daysTo (self, QDateTime)
• bool isNull (self)
• bool isValid (self)
• int msecsTo (self, QDateTime)
• int secsTo (self, QDateTime)
• setDate (self, QDate date)
• setMSecsSinceEpoch (self, int msecs)
• setTime (self, QTime time)
• setTime_t (self, int secsSince1Jan1970UTC)
• setTimeSpec (self, Qt.TimeSpec spec)
• QTime time (self)
• Qt.TimeSpec timeSpec (self)
• QDateTime toLocalTime (self)
• int toMSecsSinceEpoch (self)
• datetime.datetime toPyDateTime (self)
• QString toString (self, Qt.DateFormat format = Qt.TextDate)
• QString toString (self, QString format)
• int toTime_t (self)
• QDateTime toTimeSpec (self, Qt.TimeSpec spec)
• QDateTime toUTC (self)

Static Methods

• QDateTime currentDateTime ()
• QDateTime currentDateTimeUtc ()
• int currentMSecsSinceEpoch ()
• QDateTime fromMSecsSinceEpoch (int msecs)
• QDateTime fromString (QString string, Qt.DateFormat format = Qt.TextDate)
• QDateTime fromString (QString s, QString format)
• QDateTime fromTime_t (int secsSince1Jan1970UTC)

Special Methods

• int __bool__ (self)
• bool __eq__ (self, QDateTime other)
• bool __ge__ (self, QDateTime other)
• bool __gt__ (self, QDateTime other)
• int __hash__ (self)
• bool __le__ (self, QDateTime other)
• bool __lt__ (self, QDateTime other)
• bool __ne__ (self, QDateTime other)
• str __repr__ (self)

A Python datetime object may be used whenever a QDateTime is expected.

The QDateTime class provides date and time functions.

A QDateTime object contains a calendar date and a clock time (a "datetime"). It is a combination of the QDate and QTime classes. It can read the current datetime from the system clock. It provides functions for comparing datetimes and for manipulating a datetime by adding a number of seconds, days, months, or years.

A QDateTime object is typically created either by giving a date and time explicitly in the constructor, or by using the static function currentDateTime() that returns a QDateTime object set to the system clock's time. The date and time can be changed with setDate() and setTime(). A datetime can also be set using the setTime_t() function that takes a POSIX-standard "number of seconds since 00:00:00 on January 1, 1970" value. The fromString() function returns a QDateTime, given a string and a date format used to interpret the date within the string.

The date() and time() functions provide access to the date and time parts of the datetime. The same information is provided in textual format by the toString() function.

QDateTime provides a full set of operators to compare two QDateTime objects where smaller means earlier and larger means later.

You can increment (or decrement) a datetime by a given number of milliseconds using addMSecs(), seconds using addSecs(), or days using addDays(). Similarly you can use addMonths() and addYears(). The daysTo() function returns the number of days between two datetimes, secsTo() returns the number of seconds between two datetimes, and msecsTo() returns the number of milliseconds between two datetimes.

QDateTime can store datetimes as local time or as UTC. QDateTime.currentDateTime() returns a QDateTime expressed as local time; use toUTC() to convert it to UTC. You can also use timeSpec() to find out if a QDateTime object stores a UTC time or a local time. Operations such as addSecs() and secsTo() are aware of daylight saving time (DST).

Note: QDateTime does not account for leap seconds.

QDate uses the Gregorian calendar in all locales, beginning on the date 15 October 1582. For dates up to and including 4 October 1582, the Julian calendar is used. This means there is a 10-day gap in the internal calendar between the 4th and the 15th of October 1582. When you use QDateTime for dates in that epoch, the day after 4 October 1582 is 15 October 1582, and the dates in the gap are invalid.

The Julian to Gregorian changeover date used here is the date when the Gregorian calendar was first introduced, by Pope Gregory XIII. That change was not universally accepted and some localities only executed it at a later date (if at all). QDateTime doesn't take any of these historical facts into account. If an application must support a locale-specific dating system, it must do so on its own, remembering to convert the dates using the Julian day.

The range of valid dates is from January 2nd, 4713 BCE, to sometime in the year 11 million CE. The Julian Day returned by QDate.toJulianDay() is a number in the contiguous range from 1 to overflow, even across QDateTime's "date holes". It is suitable for use in applications that must convert a QDateTime to a date in another calendar system, e.g., Hebrew, Islamic or Chinese.

The Gregorian calendar was introduced in different places around the world on different dates. QDateTime uses QDate to store the date, so it uses the Gregorian calendar for all locales, beginning on the date 15 October 1582. For dates up to and including 4 October 1582, QDateTime uses the Julian calendar. This means there is a 10-day gap in the QDateTime calendar between the 4th and the 15th of October 1582. When you use QDateTime for dates in that epoch, the day after 4 October 1582 is 15 October 1582, and the dates in the gap are invalid.

QDateTime.__init__ (self)

Constructs a null datetime (i.e. null date and null time). A null datetime is invalid, since the date is invalid.

See also isValid().

QDateTime.__init__ (self, QDateTime other)

Constructs a datetime with the given date, a valid time(00:00:00.000), and sets the timeSpec() to Qt.LocalTime.

QDateTime.__init__ (self, QDate)

Constructs a datetime with the given date and time, using the time specification defined by spec.

If date is valid and time is not, the time will be set to midnight.

QDateTime.__init__ (self, QDate date, QTime time, Qt.TimeSpec timeSpec = Qt.LocalTime)

Constructs a copy of the other datetime.

QDateTime.__init__ (self, int y, int m, int d, int h, int m, int s = 0, int msec = 0, int timeSpec = 0)

QDateTime QDateTime.addDays (self, int days)

Returns a QDateTime object containing a datetime ndays days later than the datetime of this object (or earlier if ndays is negative).

See also daysTo(), addMonths(), addYears(), and addSecs().

QDateTime QDateTime.addMonths (self, int months)

Returns a QDateTime object containing a datetime nmonths months later than the datetime of this object (or earlier if nmonths is negative).

See also daysTo(), addDays(), addYears(), and addSecs().

QDateTime QDateTime.addMSecs (self, int msecs)

Returns a QDateTime object containing a datetime msecs miliseconds later than the datetime of this object (or earlier if msecs is negative).

See also addSecs(), msecsTo(), addDays(), addMonths(), and addYears().

QDateTime QDateTime.addSecs (self, int secs)

Returns a QDateTime object containing a datetime s seconds later than the datetime of this object (or earlier if s is negative).

See also addMSecs(), secsTo(), addDays(), addMonths(), and addYears().

QDateTime QDateTime.addYears (self, int years)

Returns a QDateTime object containing a datetime nyears years later than the datetime of this object (or earlier if nyears is negative).

See also daysTo(), addDays(), addMonths(), and addSecs().

QDateTime QDateTime.currentDateTime ()

Returns the current datetime, as reported by the system clock, in the local time zone.

See also currentDateTimeUtc(), QDate.currentDate(), QTime.currentTime(), and toTimeSpec().

QDateTime QDateTime.currentDateTimeUtc ()

Returns the current datetime, as reported by the system clock, in UTC.

This function was introduced in Qt 4.7.

See also currentDateTime(), QDate.currentDate(), QTime.currentTime(), and toTimeSpec().

int QDateTime.currentMSecsSinceEpoch ()

Returns the number of milliseconds since 1970-01-01T00:00:00 Universal Coordinated Time. This number is like the POSIX time_t variable, but expressed in milliseconds instead.

See also currentDateTime(), currentDateTimeUtc(), toTime_t(), and toTimeSpec().

QDate QDateTime.date (self)

Returns the date part of the datetime.

See also setDate(), time(), and timeSpec().

int QDateTime.daysTo (self, QDateTime)

Returns the number of days from this datetime to the other datetime. If the other datetime is earlier than this datetime, the value returned is negative.

See also addDays(), secsTo(), and msecsTo().

QDateTime QDateTime.fromMSecsSinceEpoch (int msecs)

Returns a datetime whose date and time are the number of milliseconds, msecs, that have passed since 1970-01-01T00:00:00.000, Coordinated Universal Time (Qt.UTC). On systems that do not support time zones, the time will be set as if local time were Qt.UTC.

Note that there are possible values for msecs that lie outside the valid range of QDateTime, both negative and positive. The behavior of this function is undefined for those values.

This function was introduced in Qt 4.7.

See also toTime_t() and setTime_t().

QDateTime QDateTime.fromString (QString string, Qt.DateFormat format = Qt.TextDate)

Returns the QDateTime represented by the string, using the format given, or an invalid datetime if this is not possible.

Note for Qt.TextDate: It is recommended that you use the English short month names (e.g. "Jan"). Although localized month names can also be used, they depend on the user's locale settings.

QDateTime QDateTime.fromString (QString s, QString format)

Returns the QDateTime represented by the string, using the format given, or an invalid datetime if the string cannot be parsed.

These expressions may be used for the date part of the format string:

Note: Unlike the other version of this function, day and month names must be given in the user's local language. It is only possible to use the English names if the user's language is English.

These expressions may be used for the time part of the format string:

All other input characters will be treated as text. Any sequence of characters that are enclosed in singlequotes will also be treated as text and not be used as an expression.

 QTime time1 = QTime.fromString("131", "HHh");
 // time1 is 13:00:00
 QTime time1 = QTime.fromString("1apA", "1amAM");
 // time1 is 01:00:00

 QDateTime dateTime2 = QDateTime.fromString("M1d1y9800:01:02",
                                             "'M'M'd'd'y'yyhh:mm:ss");
 // dateTime is 1 January 1998 00:01:02

If the format is not satisfied an invalid QDateTime is returned. The expressions that don't have leading zeroes (d, M, h, m, s, z) will be greedy. This means that they will use two digits even if this will put them outside the range and/or leave too few digits for other sections.

 QDateTime dateTime = QDateTime.fromString("130", "Mm"); // invalid

This could have meant 1 January 00:30.00 but the M will grab two digits.

For any field that is not represented in the format the following defaults are used:

For example:

 QDateTime dateTime = QDateTime.fromString("1.30.1", "M.d.s");
 // dateTime is January 30 in 1900 at 00:00:01.

QDateTime.toString() QTime.toString()

See also QDate.fromString(), QTime.fromString(), and QDate.toString().

QDateTime QDateTime.fromTime_t (int secsSince1Jan1970UTC)

Returns a datetime whose date and time are the number of seconds that have passed since 1970-01-01T00:00:00, Coordinated Universal Time (Qt.UTC). On systems that do not support time zones, the time will be set as if local time were Qt.UTC.

This function was introduced in Qt 4.2.

See also toTime_t() and setTime_t().

bool QDateTime.isNull (self)

Returns true if both the date and the time are null; otherwise returns false. A null datetime is invalid.

See also QDate.isNull(), QTime.isNull(), and isValid().

bool QDateTime.isValid (self)

Returns true if both the date and the time are valid; otherwise returns false.

See also QDate.isValid() and QTime.isValid().

int QDateTime.msecsTo (self, QDateTime)

Returns the number of milliseconds from this datetime to the other datetime. If the other datetime is earlier than this datetime, the value returned is negative.

Before performing the comparison, the two datetimes are converted to Qt.UTC to ensure that the result is correct if one of the two datetimes has daylight saving time (DST) and the other doesn't.

This function was introduced in Qt 4.7.

See also addMSecs(), daysTo(), and QTime.msecsTo().

int QDateTime.secsTo (self, QDateTime)

Returns the number of seconds from this datetime to the other datetime. If the other datetime is earlier than this datetime, the value returned is negative.

Before performing the comparison, the two datetimes are converted to Qt.UTC to ensure that the result is correct if one of the two datetimes has daylight saving time (DST) and the other doesn't.

Example:

 QDateTime now = QDateTime.currentDateTime();
 QDateTime xmas(QDate(now.date().year(), 12, 25), QTime(0, 0));
 qDebug("There are %d seconds to Christmas", now.secsTo(xmas));

See also addSecs(), daysTo(), and QTime.secsTo().

QDateTime.setDate (self, QDate date)

Sets the date part of this datetime to date. If no time is set, it is set to midnight.

See also date(), setTime(), and setTimeSpec().

QDateTime.setMSecsSinceEpoch (self, int msecs)

Sets the date and time given the number of milliseconds,msecs, that have passed since 1970-01-01T00:00:00.000, Coordinated Universal Time (Qt.UTC). On systems that do not support time zones this function will behave as if local time were Qt.UTC.

Note that there are possible values for msecs that lie outside the valid range of QDateTime, both negative and positive. The behavior of this function is undefined for those values.

This function was introduced in Qt 4.7.

See also toMSecsSinceEpoch() and setTime_t().

QDateTime.setTime (self, QTime time)

Sets the time part of this datetime to time.

See also time(), setDate(), and setTimeSpec().

QDateTime.setTime_t (self, int secsSince1Jan1970UTC)

Sets the date and time given the number of seconds that have passed since 1970-01-01T00:00:00, Coordinated Universal Time (Qt.UTC). On systems that do not support time zones this function will behave as if local time were Qt.UTC.

See also toTime_t().

QDateTime.setTimeSpec (self, Qt.TimeSpec spec)

Sets the time specification used in this datetime to spec.

See also timeSpec(), setDate(), setTime(), and Qt.TimeSpec.

QTime QDateTime.time (self)

Returns the time part of the datetime.

See also setTime(), date(), and timeSpec().

Qt.TimeSpec QDateTime.timeSpec (self)

Returns the time specification of the datetime.

See also setTimeSpec(), date(), time(), and Qt.TimeSpec.

QDateTime QDateTime.toLocalTime (self)

Returns a datetime containing the date and time information in this datetime, but specified using the Qt.LocalTime definition.

See also toTimeSpec().

int QDateTime.toMSecsSinceEpoch (self)

Returns the datetime as the number of milliseconds that have passed since 1970-01-01T00:00:00.000, Coordinated Universal Time (Qt.UTC).

On systems that do not support time zones, this function will behave as if local time were Qt.UTC.

The behavior for this function is undefined if the datetime stored in this object is not valid. However, for all valid dates, this function returns a unique value.

This function was introduced in Qt 4.7.

See also toTime_t() and setMSecsSinceEpoch().

datetime.datetime QDateTime.toPyDateTime (self)

QString QDateTime.toString (self, Qt.DateFormat format = Qt.TextDate)

Returns the datetime as a string. The format parameter determines the format of the result string.

These expressions may be used for the date:

These expressions may be used for the time:

All other input characters will be ignored. Any sequence of characters that are enclosed in singlequotes will be treated as text and not be used as an expression. Two consecutive singlequotes ("''") are replaced by a singlequote in the output.

Example format strings (assumed that the QDateTime is 21 May 2001 14:13:09):

If the datetime is invalid, an empty string will be returned.

See also QDate.toString() and QTime.toString().

QString QDateTime.toString (self, QString format)

This is an overloaded function.

If the format is Qt.TextDate, the string is formatted in the default way. QDate.shortDayName(), QDate.shortMonthName(), and QTime.toString() are used to generate the string, so the day and month names will be localized names. An example of this formatting is "Wed May 20 03:40:13 1998".

If the format is Qt.ISODate, the string format corresponds to the ISO 8601 extended specification for representations of dates and times, taking the form YYYY-MM-DDTHH:mm:ss[Z|[+|-]HH:mm], depending on the timeSpec() of the QDateTime. If the timeSpec() is Qt.UTC, Z will be appended to the string; if the timeSpec() is Qt.OffsetFromUTC the offset in hours and minutes from UTC will be appended to the string.

If the format is Qt.SystemLocaleShortDate or Qt.SystemLocaleLongDate, the string format depends on the locale settings of the system. Identical to calling QLocale.system().toString(datetime, QLocale.ShortFormat) or QLocale.system().toString(datetime, QLocale.LongFormat).

If the format is Qt.DefaultLocaleShortDate or Qt.DefaultLocaleLongDate, the string format depends on the default application locale. This is the locale set with QLocale.setDefault(), or the system locale if no default locale has been set. Identical to calling QLocale().toString(datetime, QLocale.ShortFormat) or QLocale().toString(datetime, QLocale.LongFormat).

If the datetime is invalid, an empty string will be returned.

Warning: The Qt.ISODate format is only valid for years in the range 0 to 9999. This restriction may apply to locale-aware formats as well, depending on the locale settings.

See also QDate.toString(), QTime.toString(), and Qt.DateFormat.

int QDateTime.toTime_t (self)

Returns the datetime as the number of seconds that have passed since 1970-01-01T00:00:00, Coordinated Universal Time (Qt.UTC).

On systems that do not support time zones, this function will behave as if local time were Qt.UTC.

Note: This function returns a 32-bit unsigned integer, so it does not support dates before 1970, but it does support dates after 2038-01-19T03:14:06, which may not be valid time_t values. Be careful when passing those time_t values to system functions, which could interpret them as negative dates.

If the date is outside the range 1970-01-01T00:00:00 to 2106-02-07T06:28:14, this function returns -1 cast to an unsigned integer (i.e., 0xFFFFFFFF).

To get an extended range, use toMSecsSinceEpoch().

See also toMSecsSinceEpoch() and setTime_t().

QDateTime QDateTime.toTimeSpec (self, Qt.TimeSpec spec)

Returns a copy of this datetime configured to use the given time specification.

See also timeSpec(), toUTC(), and toLocalTime().

QDateTime QDateTime.toUTC (self)

Returns a datetime containing the date and time information in this datetime, but specified using the Qt.UTC definition.

See also toTimeSpec().

int QDateTime.__bool__ (self)

bool QDateTime.__eq__ (self, QDateTime other)

bool QDateTime.__ge__ (self, QDateTime other)

bool QDateTime.__gt__ (self, QDateTime other)

int QDateTime.__hash__ (self)

bool QDateTime.__le__ (self, QDateTime other)

bool QDateTime.__lt__ (self, QDateTime other)

bool QDateTime.__ne__ (self, QDateTime other)

str QDateTime.__repr__ (self)